Fluid fuel combustion apparatus and control therefor



May 15, 1951 Filed Oct. 5, 1945 W. L. RIEHL FLUID FUEL comsus'rzouAPPARATUS AND CONTROL THEREFOR 2 Sheets-Sheet 1 May 15, 1951 w. L. RIEHL2,553,062

FLUID FUEL COMBUSTION APPARATUS AND CONTROL VTHEREFOR Filed Oct. 5, 1945I 2 Sh ets-Sheet 2 Fig. 4

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gi @daw/VQM i atented May 15, 195i William L. Riehl,;Marey, N. Yassignor to Union Fork & H e Company, Columbus, Ohio, a corporation ofOhio Application was 1945, sea-1" o; 6203514 This invention relates tocombustion apparatus and" is particularly useful for such apparatus whensupplied with'fluid' fuel.

An object of the invention is to provide an 1m proved combustion"apparatus which will insure efficient combustion of fuel.

Another object is to. provide an improved combustion apparatus whichwill be composed'of few and simple parts.

Another object is to provide an improved combustionapparatus which: maybe easily and economically manufactured.

Another object is to provide animproved com"- bustion apparatus'whichwill control combustion accurately in accordance with heat requirements.

Another object 'is'to provide an improved'com-- bustion apparatus whichwill be extremely safe.

Another object'is'to provide an iinprovedcornbustion apparatuswhich'will be fully automatic in its operation.-

Another object is to providean improved com bustion apparatus which willeffect its control through a single valve.

Other objects will hereinafter appear.

Thejnvention will be better understoodfro'm the description of twopractical embodiments thereof, illustrated in the accompanying drawings,in which;

Figure 1 is a somewhat fragmentary sectional view of a control apparatusdesigned'ior the handling of gaseous fuel and for burning this fuelunder sub-atmospheric pressures, electrical circuits being showndiagrammatically; and parts of the apparatus broken away;

Figure 2 i a diagrammatic representation "of" certain parts of theapparatus of'Figure 1 showing their control circuits; Figure 3 is awiring diagram similar to Figure"2,

but showing control circuits as they maybe ar ranged when a plurality ofunits are usedtogeth'er connected to a single source of sub-atmosphericpressure or for one or more units arranged for" combustion aboveatmospheric pressure;

Figure 4 is aview similar to Figure 1 showing a modified form ofapparatus arranged'for burning fuel at pressures above atmospheric;

Figure dis a fragmentaryelevational View of a" modified formofthermostat mechanism'similar" to that shown in Figures 1 and 4;

Figure 6 is a transverse sectional view taken on" the line VI-VI ofFigure 5; and

bustion chamber is shown at lfthis being'proseams. (c1. is's' -iiufvided with a removable bottom or plate 2 secured to the chamber as byscrews 3, which furnishes meansof access by which the burner 4 may he 4inserted or removed from the combustion chamber.

A conduit 5 leads from the combustion chamber to ameans'. for. reducingthe pressure within-the" combustion chamber and withdrawing gases:

therefrom, shown as a blower or pump Bdriv'en 10 by an electric. motorI.

Gas or other combustible through a conduitor pipe 8 to acontrolapparatuswhich regulates its passage to the burner U drawn through these ports bythe vacuum Sexist-a ing in thezcombustionichambervat a rate which.

will maintaincombustion suflicient to take care of the heat requirementsto be met by the apparatus.

Connectedjto the ofjconduitlaiis a 9, one branch. of whichiis connectedvby a. short piece'of p'ipe ornipple ll! ,toayalve bodylla the capbeingthreaded to the branch or the body;

PH Q Q. tha c n e ed to the n pple .l 6, and: provided with alock nut 2[,sothat valve l8may be adjusted toward orirorn the end of pipple 16,,by means'of its threaded shank and may be,

clamped in'any adjusted position by the lock nut."

Theoutletbraneh 'cf valve'bodyfll fi t iiii taif fli lg mra -h fi t 3he. lateralbranch'of which is connected to apiece of pipe 24 carrying atits end a valve .or stopcock 25 'bywhi ch' air may be admitted and itsadmission regulated;

The remaining barrehtr aagzs is @nhaaf byme aiis of a tube 26 'to'thebottom of the bumi'i'al A q H, rro m fi- 9, a street elbow 2 l connectswith electrically controlled valvefllZS and from valve a tube 29 extendsto the outer sleeve iw of fluid is supplied connected by ai.

3 a pilot burner, thus bypassing fuel around valve l3;

In the interior of this burner is secured a cylindrical ceramic holder31, substantially concentric with sleeve 30, which carries a coil ofresistance wire 32, the sleeve and holder being spaced apart throughouttheir peripheries and the wire being so positioned that a film of gasmay pass up through the annular space between the sleeve 35 and centralholder 3|, issuingv exterior of holder 3|, or may be separate therefrom, as a ring of corrugated sheet metal.

Depending from the valve I3 is a stem 33 which 4 pansible material, andstainless steel is found to be very satisfactory for this part.

The bottom of the tube is threaded into the top of a housing as securedto plate 2, and the housing carries'two switches 55 and 55 which may beadjusted toward and from the depending arm or lever 52 by means of setscrews 57.

The upper perforated part of tube 50 is, of course, in very closeproximity to the flame of the pilot burner which emanates from the topof tube 35, so that the side of the tube 55 closest adjacent this flamewill, while the flame is burning, be heated to a higher temperature thanthe side remote therefrom, and the differential expansion of thetwosides of the tube cause it when heated to bend slightly to the rightas seen in Figure 1, movingthe lower end of lever arm 52 to extendsthrough a somewhat larger perforation in the boss l5 into the spacewithin a casing secured to this boss, 'the casing consisting of an upperpart or top 34 and a lower part or bottom 35, these parts being securedtogether by means The upward movement of the valve stem 33 which permitsthe closing of switch 42 before valve [3 opens, is permitted by theclearance provided by the slidable telescopic arrangement of the upperend of valve stem 33 and its reception in the recess of the dependinghub of valve [3.

Thus, it will be seen that the space between the diaphragm 3'! and upperhousing section 34 is subjected to the reduced pressure which exists inthe. discharge side of the valve body H and that the bottom of thediaphragm is exposed to atmospheric pressure entering through theperforation around valve stem end 39.

Consequently, a differential pressure tending to move the diaphragm upexists only when a subatmospheric pressure is present in the combustionchamber, from which it is transmitted to the discharge side of valve l3.

- Above valve l3 and directly in alignment therewith is a disc orplunger 45 carried by rod 46,

the disc being pressed toward the valve by a spring 47, and capable ofbeing retracted therefrom by an electric motor 48 contained within ahousing 49, threaded on boss I4 of valve body II.

The tension of spring 4'! must, of course, be sufficient to overcome thevalve-opening force of diaphragm 3i, and the motor 48 must have enoughpower to retract the plunger 45 against the pressure of the spring, sothat the plunger 45 through the tube. The tube may be of any ex-;

the left, and thus opening switch 55 and closing switch 56. The motionof the tube top is magnified by lever 52 which is substantially longerthan the tube, as shown..

In the absence of flame from either the pilot or main burner, tube againresumes its vertical position, opening switch 55 and closing switch 55.

Current is supplied to motor I by conductors 58 and 59, the currentcoming from power lines 53 and 5!, the former of which is connecteddirectlyto line 59 and the latter of which is connected through anelectro-magnetically controlled switch 52 to conductor 58.

Arranged in parallel with switch 52 is the primary 33 of a transformer,the secondary 5d of which is connected by conductor 55 to the coil 36which actuates switch 52, this coil being connected in turn by conductor55 to a room thermostat 58, theopposite side of which is connected tosecondary 64.

Thus, it will be seen that whenever heat is required, the contacts ofthermostat 58 close, completing the circuit through secondary 6d andcoil 55, closing the circuit to motor I, while as soon as thetemperature has risen sufiiciently to open the contacts of thermostat58, switch 32 is opened,

discontinuing the supply of current tomotor I. Figure 2 shows thecircuits controlling the supply of fuel, these circuits being suppliedby current from the main power line through a plug 55 and conductors 55which convey this current to the primary H of another transformer.

From the transformer secondary '52 extend conductors 73 and M. Inconductor '54 is interposed switch 42, and this conductor terminates atthe switches 55 and 55. Connected to conductor '13 and to conductor 14between switch 42 and "switches 55 and 55 is the coil of valve 23, whilevalve motor 43 is connected between conductor 73 to switch 55. v I

Conductor i3 terminates at the ignition coil 32, from which a conductor35 extends to switch 55.

The operation of the device described is as follows:

Until there is.a demand for heat, thermostat 68 remains open and themotor l cannot operate. In this condition, there is atmospheric pressurein the combustion chamber and above diaphragm 31, so that the diaphragmremains in its lowermost position (as shown in Figure l), holding switch42 open and preventing any current from passing through the circuits ofFigure 2.

Of course, the valve I3 is closed upon its seat l2, and the spring 51presses the disc :35 tightly down upon it to hold it .there.Consequently, no

gas can pass through the main line to the burner.

Similarly, valve 28 is closed, as no current is ZJQQiQQQ housing 34above diaphragm 3'1. 1Q

This reduction in pressure above the diaphragm permits the atmosphericair pressing uponits lower surface to raise the diaphragm slightly untilthe end of valve stem 33, contacts valve I3, which allows switch 42 toclose.

Current now may travel through the coil of switch 28 and switch 42,causing the valve. at23 to open and admit a pilot supply of g as to the.e 30,

At this stage, thermostat tube 501s cool, hence switch 55 is closedandswitch 56 is open,

Current, therefore, cannot pass through motor 48, but does passthroughignition coil 32, con: ductor [5, switch 55, back to conductor 14,causing the ignition coil to become incandescent and to ignite the gaswhich emerges from, tubeBG.

The pilot flame, heating thermostat tube 50, causes this to bend to theright, swinging the lower end of arm 52 to the left and thus openingswitch 55 and closing switch 56. 30

The opening of the former switch breaksthe circuit through the ignitioncoil, while the closing of the latter completes the circuit throughmotor 48 which immediately retracts the stem IIiand disc 45 from valve I3, permitting thisvalve to functionfreely. as the diaphragm 31 riseswith. the increase of suction above it.

Thus, gasis admitted. not onlyto thepilot burner, but to the mainburner, which latter .flow. is ignited by the flame ofthepilotburner,and. valve I3 is controlledby thesuction as longas these conditionsobtain.

As soon, however, as the need for heat" has been met, the contacts ofthermostat BB open, and motor I .isstQpped. Immediately the presuWithin. the .combu'stionchamber rises and is transmitted to.theuppersideof diaphragm 31, causing'it to drop.and.to open switch 42;.break ing the circuits th'roughvalve 28.,and-motor 48, and thus.closing. boththepilot valve 28 and the main valve I3.

Assoon as theflame within the combustion chamber has burned out,thermostat 5!! moves to the left; again closing switch. 55.1 and openingswitch 56, so that the parts. are readyrtofunction. .55 through theircycleagain upon the .next-actuae tion of thermostat 68.,

It willbe noted that no gas may be admitted through valve I3 or28funless the properoperationofthe suction fanhas commencegl and that l'asmw P s a ve '3 un es aflameexists. at the pilot burner. Gas maybeadmittedtojhq. pilot burner only when a proper vacuum exists andsimultaneously with thesupply of current 7 to the ignition coil. 7

'The'valve I 3'being controlledby the diaphragm 31 which is'actuated'b'y' the pressure difierential betwee'n the atmosphere and thepressure in. the conduit beyond the valve acts as a regulat r of flowo'r'pressure in" that portionlof'ltheconduit 70 between it and theorifice valvelfi, so. that it is in'effect a combined pressure regulator'and ma fuel valve. Its operation ion atmospheric pressur and acuum make"it also a .vaai umssray Syn The" speed with. which thejvalve react on Ilicen e dep nd nt. u on. t e ime nccessarr;.-te

exha st ases, irom. he sp ce. above. diaphra m. 3. 9 5.0. m rbedetermind by the. amount Iot-= pac whic is eft-in he n n througnit-ne. boss l5and around shank 33. If it. is -.desired to.

' i ure h v lveper t n slowly, Wi ho abrup jar, b s On n ssary. torestri t the o le lin about thestem 33, it only being, necessary that.there be suflicient space for gas to be drawn alonge. side the stem.

Figure. 3; is shown, a. modification, Ofdlihflfllm cuit of Figure 2, theonly change being the. i113e1 tion of theroom thermostatl 68 inthe lineI 13 -im.-.

mediately adjacent the secondary 1 2 of the-trans.

former.

This circuit is intended for use Where a. num-. ber of unitssuchasshownin Figure 1. are; con-.. nected to a common blower which is.operatect continuously,

In these circumstances, when the need for heat:

arises, thermostat I68 closes and completesthe circuits through thepilot controlavalve 2&, .-themotor 48 and the ignition coil 32 directly,instead of through creating the suction. The; switch 42-preventsanyundesired supply of -gasi should the common, blower be outof,operation-,;

but otherwise the cycle of, operation is precisely, the same as thatabove. described.v

In Figure 4 is shown an arrangement ofv the, control of Figure 1whichhasbeenv adapted to;

systems which are not operated belowv atmos pheric pressure.

The only structural changes in theapparatus are that the casing bottomhas been replacedawith a casing bottom I35 which, instead... of:carrying a switch 42,; has, a depending; central-,- boss MI carrying aspring I42bearing. directly; on the lower diaphragm plate, from whichpres-a. sure is transmitted to the headAE! atithe lower. end of the stem33,, and theswitch 42 has been-'.

omitted. The gas pressure on the uppersure.

face of diaphragm 3! acts, against ,the.atmos-,,.

pheric pressure on the lower side of this vdia-. phragm, plus thepressure of spring I42, which, of course, is adjusted ,so that anyexcessive gas pressure will overcome theiorce of the spring.I Thepressure in.v the conduit beyond valve I3 is somewhat above andpermitthe valve to close,

atmospheric, as it must be suflicient to cause sufiia cient fuel to flowpast the restricted portion of E the conduit, as in the case of the.first described;

Beyond this vsection the velocity of the gas, as well as the draftcreated by the stack, are sumcient to draw inadequate air to;

embodiment.

support combustion.

The diaphragm 3?, in this embodiment, serves; to control the opening ofvalve I3 from, its seatv I2 according to the pressure which existsinconlimiting the possible opening motion of valve l3 in accordancewiththe supply of current to the motor, which current in turn is controlledby v room thermostat I 68.

The control circuit, in this instance is precise ly the same as thatshown in Figure 3, with the omission of switch 42.

It will be seen that the main valve is maintained closed unless a flameexists toignite theiueL; and that the electric ignition. is controlled.as,

above described.

In Figure 5, a modification of the-thermos static device of thepreceding figures is shown, in which the tubular element has beenprovided with two elongated diametrically spaced slots instead of theseries of perforations 53 of the preceding figures.

In this form, the tubular element is shown at 250, it having a'closedupper end 25!, and two diagrammatically disposed elongatedaxiallyextending slots 253.

The central lever 252 is clamped within the closed end 25l, as in thefirst figure, but extends ,at its lower end into a fitting 254 in theform of a conventional pipe-T, where it is connected to a rod 255extending laterally through the side branch of the T and through afitting 256', to which is clamped a diaphragm'25'l by means of a ring258, which seals the space about the rod 255. The end of the rod engagesa switch 259, corresponding to switch 55 of the preceding figures.

The lower branch of the T is conveniently closed by a plug 260.

In Figure 7 the slots 353, are shown as penetrating nearly but not quitethrough the tubular element 350. The thin remaining portions of. thewall where defined by these slots or slot-like grooves are so small thatheat is not readily conducted through them, and the action is preciselythe same as that of the preceding modifications, excepting that withthis form of the device, the interior of the tubular element is sealedfrom the sub-atmospheric pressure of the combustion chamber, and'thediaphragm 25'? or other sealing means may, therefore, be eliminated.

While I have described the illustrated embodiments of my inventionin'some particularity, obviously many other embodiments, variations, andmodifications will readily occur to those skilled in this art, and I donot, therefore, limit myself to the precise details shown and describedherein, but claim as my invention all embodiments, modifications andvariations coming Within the scope of the appended claims.

I claim:

1. In a combustion apparatus including a combustion chamber, poweroperated exhausting means connected therewith, a burner in said chamberand 'fuel conducting means connected therewith, a valve interposed insaid fuel conducting means, pressure responsive operating meansoperatively associated with said valve controlled by the difference inpressure between that existing at the burner and that of the atmosphereand capable of opening and closing the same, closing and holding meansoperatively associated with said valve, resilient means Luging saidclosing and holding means into valve closing position, electricalretractin means capable of moving said closing and holding means fromvalve closing position, and control means for said closing andretractingmeans controlled by the presence or absence of a flame at said burner.

2. In a combustion apparatus including a combustion chamber, poweroperated exhausting means connected therewith, a burner in said chamberand fuel conducting means connected therewith, a valve interposed insaid fuel consaid closing and holding means into valve'closing position,electrical retracting means capable of moving said closing and holdingmeans from valve closin position, and control means for said closing andretracting means controlled by the presence or absence of a flame atsaid burner, said pressure responsive means having limited movementindependent of said valve, and a control actuated by said pressureresponsive means during said limited movement preventing release of saidvalve holdin means until the pressure responsive means has completed itslimited movement.

3. In a combustion apparatus including a combustion chamber, poweroperated exhausting means connected therewith, a burner in said chamberand fuel'conducting means connected therewith, a valve'interposed insaid fuel conducting means, pressure responsive operating meansoperatively associated with said valve and responsive topressure'changes in the fuel conducting means between the valve and theburner, closing and holding means associated with said valve, includingresilient means capable of closing the valve against the pressureresponsive operating means and electrical means capable of moving saidclosing and holding means to position permitting the valve to open andcontrolled by the presence or absence of flame at said burner,saidpressure responsive means having limited movementindependent of saidvalve, and a control actuated by said pressure responsive means duringsaid limited movement preventing release of said valve holding meansuntil the pressure responsive means has completed its limited movement,branch conduit means from the fuel conducting means on the side of thevalve remote from the burner to a pilot burner adjacent said firstmentioned burner, and a control valve in said branch conduit meanscontrolled by the pres sure responsive means during its independentmovement. a

4. In a combustion apparatus comprising a combustion chamber, a mainburner therein, a source of fluid fuel under pressure, a conduitconnecting said source of fuel with said'burner, a branch conduit fromsaid first mentioned conduit, a pilot burner connected to said branchconduit and adjacent said main burner in said I combustion chamber, asource of suction connected to said combustion chamber, a valve in saidmain conduit between the branch conduit and the main burner, a pressureresponsive element operatively associated with said valve and havinglimited movement with respect thereto when the valve is seated, a valvecontacting element arranged to engage the valve and urge the same towardits seat, a, spring operatively associated with saidvalve contactingelement and. capable of pressing the valve against its seat: andovercoming the pressure of the pressure re-- retracting; means connectedto said valve contacting eleoperatively associated withsaid valve andca-V pable of moving it from its seat, a plunger in alignment with saidvalve, a compression spring urging the plunger against the valve, andelectro-magnetic means arranged to retract the plunger against thepressure of the spring.

6. In a combustion controlling apparatus a valve comprising a bodyhaving a seat, a valve having a head movable into and out of engagementwith said seat, a diaphragm operatively associated with said valve andcapable of moving it from its seat, a plunger in alignment with saidvalve, a compression spring urging the plunger against the valve, andelectro-magnetic means arranged to retract the plunger against thepressure of the spring.

7. In a combustion controlling apparatus a valve comprising a bodyhaving a seat, a valve having a head movable into and out of engagementwith said seat, a diaphragm operatively associated with said valve andcapable of moving it from its seat, a plunger in alignment with saidvalve, a compression spring urging the plunger against the valve, andelectro-magnetic means arranged to retract the plunger against thepressure of the spring, the diaphragm being movable after the valve isseated; and means limiting the movement of said diaphragm.

8. In a combustion apparatus comprising a combustion chamber, a sourceof fluid fuel under pressure, a conduit from said source of fuel to saidcombustion chamber and terminating in a main burner, a branch conduitfrom said first mentioned conduit to said combustion chamber andterminating in a pilot burner, a valve in said conduit between thebranch conduit and the main burner, pressure responsive means capable ofopening said valve operatively associated therewith and having a limitedmovement independent of said valve, resilient valve holding meansoperatively associated with said valve and controlled by electricallyoperated retracting means, an electrically operated control valve in thebranch conduit, a thermostat adjacent both burners, a switch operated bysaid thermostat, a second switch operated by the movement of thepressure responsive means independent of the valve, a control circuitincluding a source of power, the pressure operated switch and the branchconduit valve and a circuit in parallel with said branch conduit valveincluding the thermostatically actuated switch and the valve holderretracting means, a second switch actuated by the thermostat alternatelywith the first mentioned switch and an electrical igniter in circuitwith said second thermostatically actuated switch.

9. In a combustion apparatus comprising a combustion chamber, a sourceof fluid fuel under pressure, a conduit from said source of fuel to saidcombustion chamber and terminating in a main burner, a branch conduitfrom said first mentioned conduit to said combustion chamber andterminating in a pilot burner, a valve in said conduit between thebranch conduit and the main burner, pressure responsive means capable ofopening said valve operatively associated therewith and having a limitedmovement independent of said valve, resilient valve holding meansoperatively associated with said valve and controlled by electricallyoperated retracting means, an electrically operated control valve in thebranch conduit, a thermostat adjacent both burners, a switch operated bysaid thermostat, a second switch operated by the movement of thepressure responsive means independent of the valve, a control circuitincluding a source of power, the pressure operated switch and the branchconduit valve and a circuit in parallel with said branch conduit valveincluding the thermostatically actuated switch and the valve holderretracting means, a second switch actuated by the thermostat alternatelywith the first mentioned switch.

W. L. RIEHL.

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